Laser guidelines have been widely used in industry as visual references for cutting, folding, bending, etc. In its use as a guideline, the laser is required to draw a fine line of light on an object and this line is used as a guide by which cutting, folding, bending, etc. functions are achieved.
One such method employed in producing the guidelines is to rotate a polygonalprismatic mirror at a high speed in the path of a laser beam to make the reflected beam sweep the surface of an object. This method requires a plurality of parts assembled in a complicated structure for rotating the mirror.
Another alignment tool which has been resorted to is the combination of a He-Ne laser with a cylindrical lens attachment on the front for expanding the beam in one direction. However, it has been found that the laser beam varies significantly in intensity and width along its length.
U.S. Pat. No. 4,589,738, issued May 20, 1986 to Ozaki, sets forth various optical arrangements for projecting a laser beam in a linear pattern such as a line, square, etc. A convex reflector or a concave lens is used to spread a laser beam radically and a cylindrical-concave reflector is relied upon to converge the radially expanded beam linearly to project a line, square, etc. As can be understood from the foregoing description, and one drawback of this approach is that the arrangement is complex and requires a variety of optical elements in strict alignment. Another drawback is that the projected line is non-uniform in width and intensity along its length, as was discussed above in conjunction with the cylindrical lens.
A linear diverging lens is disclosed in U.S. Pat. No. 4,826,299 issued to Ian Powell on May 2, 1989. The lens is a two surface optical element with a relatively sharp radius at its apex and whose primary surface can be closely described by a one surface conical. The lens of the Powell patent, typically, is used in conjunction with a He-Ne laser beam which has an output beam having a circular configuration, and the Powell lens expands this circular beam in one direction to produce a reference line.
A major defect found in the lens of the Powell patent is that it is limited to use with the circular output of a He-Ne laser when being used as a line projector lens and cannot be used to properly function as a line projector lens when used with a laser having an output beam configuration which is non-circular such as an elliptical output beam configuration of a solid state laser diode.
However, it has been found that by using a laser diode in combination with a properly designed lens that a compact line projector device could be produced which would be simple in construction, and inexpensive. Structure of the present invention provides such line projector lens.
It is, therefore, an object of the present invention to provide a lens which will function as a line projector lens when used with a light source having other than a circular output beam configuration.
It is another object of the present invention to provide such a lens which has an anamorphic aspheric line projector surface.
It is still a further object of the present invention to provide such a lens which will function to expand an elliptical beam in one direction while compressing it in another direction to form a line of uniform width and intensity with defined ends.
These and other objects of the present invention will become more readily apparent when taken in conjunction with the accompanying drawings, specifications and claims.